In recent weeks, pollsters have started asking voters whether they would opt for a coalition of Civic Platform (PO) and Nowoczesna* (N), rather than asking which of these two parties they would vote for. I am sceptical of two things: one, the value of polls that ask about fictional coalitions; two, the likelihood of these two parties maintaining a common front for long enough to fight the 2019 election on a joint list.

There is a caveat to the caveat; these two parties have agreed to fight November's local elections on the same ticket. Yet in turn, there is also a caveat to that caveat: over the last few days, Nowoczesna have seen three prominent members abandon ship, including party founder and unceremoniously defenestrated leader Ryszard Petru. This leaves Nowoczesna a qualitatively different beast to the one it was when most of these polls were conducted.

Nevertheless, since it is likely that pollsters will continue to ask voters about their intentions toward this coalition - hopefully not at the cost of continuing to poll them on their intentions toward the component parties - I have modelled these pooled polls separately, and will return to them from time to time.

As the most recent figures show, the gap between the two major players is significantly closer if Civic Platform and Nowoczesna join forces, with the PO&N coalition on around 34% of the vote, and Law and Justice (PiS) on around 39%. For the most part, this closing of the gap can be attributed to the accumulation of the two parties' independent vote shares, but there is a 3-4% 'coalition bonus' that accrues to the joint endeavour. Nevertheless, PiS almost certainly remains ahead of PO&N.

The story among the remaining parties remains relatively unchanged. The Democratic Left Alliance (SLD) just edges into third position with around 9% of the vote, with the Kukiz'15 social movement on around 8%. Perennial rotating coalition candidate the Polish Peasant Party (PSL) just dips below the threshold, while none of the remaining parties come close to breaching it.

There is little to look at so far when it comes to trends, as there have only been six relevant polls. Nothing yet suggests that the prospect of a coalition has stimulated any movement in the direction of increased support for this initiative, but it is too early to rule out the possibility that it might.

If the current figures are translated into seats, each party's national scores weighted by its constituency-level support in 2015, then a PiS-Kukiz'15 coalition offers the only viable route to a governing majority. PiS would lose 23 seats compared with their 2015 figure, while PO&N would gain 14 compared with the combined totals for the constituent parties at the last election.

Looking at the absolute differences in seat shares for PiS (light-dark blue) and PO&N (light orange), two things stand out: PiS remains dominant in its eastern and south-eastern strongholds, and PO&N prevails - albeit less convincingly - in the west and major urban centres. This is unsurprising: there was a strong correlation between the size of Civic Platform's and Nowoczesna's constituency-level vote shares in 2015.

This suggests that the breathless response of the liberal media to this last set of polls needs to be tempered with a degree of caution. Yes, a PO&N coalition gives Poland's liberal-conservative opposition a greater overall share of the vote; and yes, there seems to be a bonus for cooperation. However, as things stand, it is likely that a significant proportion of this support will pile up in constituencies where the two parties do better than average already. In the absence of any marked decline in support for PiS, it will struggle to make significant inroads into less favourable terrain. It is not enough for the opposition to succeed; PiS must fail.

* I use Nowoczesna's Polish name rather than the awkwardly adjectival English translation "Modern".